1. Field of the Invention
The present invention relates to a camera for use with a roll photo film. More particularly, the present invention relates to a camera for use with a roll photo film, in which a leader of the roll photo film can be inserted in a take-up spool with great ease.
2. Description Related to the Prior Art
There is a roll photo film, in which a medium format photo film is wound in a roll form. The medium format photo film consists of a photo filmstrip being 6 centimeters wide and either one of backing paper and two sheets as leader and trailer. The roll photo film has a spool of which the medium format photo film is wound about a spool core. Examples of the roll photo film are the 120 and 220 types. The 120 type has the light-shielding backing paper including leader and trailer portions, the leader portion being disposed on a front end of the photo filmstrip, trailer portion being disposed on a rear end of the photo filmstrip. The 220 type has the light-shielding leader and trailer sheets, the leader sheet being disposed on a front end of the photo filmstrip, trailer sheet being disposed on a rear end of the photo filmstrip. In the core of the spool is formed an insertion slit, into which the leader is inserted when the spool is used as a take-up spool. Respective ends of the spool core have a flange. In the center of the flange is formed a shaft inserting hole.
The shaft inserting hole is constituted by a circular axial hole and a pair of key ways. The key ways are formed by cutting toward the periphery of the flange from the axial hole. When a photo film supply chamber is loaded with the roll photo film, a support shaft of the camera enters the axial hole of the shaft inserting hole to support the roll photo film in a rotatable manner. The spool being uncovered after removal of entirety of the meduim format photo film is used as the take-up spool. The key portion on the shaft portion of a drive shaft in a photo film take-up chamber comes in engagement with one of the key ways, so that rotation of the drive shaft is transmitted to the take-up spool. A cutting direction of the key ways of the shaft inserting hole is predetermined in relation of the through direction of the insertion slit.
The meduim format camera for use with the roll photo film is loaded with the spool being uncovered and derived from the roll photo film used previously in the form of the take-up spool before the roll photo film is newly loaded. The shaft inserting hole of the take-up spool is engaged with the drive shaft in the photo film take-up chamber. The roll photo film is placed in the photo film supply chamber. An end of a leader of the meduim format photo film is extended and inserted in the insertion slit of the take-up spool in the photo film take-up chamber. Operation of a winder lever or an auto-loader mechanism operable upon closing the back lid causes the drive shaft to rotate the take-up spool, for the purpose of winding the meduim format photo film about the spool core.
After taking exposures, the entirety of the meduim format photo film is wound up about the take-up spool. The back lid is opened. The take-up spool being with the photo filmstrip wound thereon after the exposures is removed from the photo film take-up chamber. The spool being uncovered in the photo film supply chamber will be used as the take-up spool in next operation of taking exposures.
During or after taking a series of exposures, the meduim format photo film is wound. A stop position of the drive shaft in the photo film take-up chamber is changed in a temporary manner of the stop, and depends on any of a length of the meduim format photo film, timing of a finish of photo film winding of the user, and timing of detection of the finish of the photo film winding. When the spool being uncovered is engaged with the drive shaft by way of the take-up spool, it is likely that the insertion slit of the take-up spool stops in an unsuitable position for insertion of the end of the leader due to the stop position of the key portion of the drive shaft. Manual operation of the winder lever or direct manual operation of the take-up spool are required for adjusting the insertion slit in consideration of receiving the leader, to complicate the handling of the camera.